Method and apparatus for distilling of solvents in which foreign matter is dissolved

ABSTRACT

A method and apparatus for distilling solvents in which foreign matter is dissolved, resulting for instance from treating of textile material. The solvent is fed in a first distilling vessel in which it is evaporated until the liquid solvents therein reaches a predetermined level, whereafter the remaining liquid solvent is discharged from the first into a second distilling vessel wherein the solvent is subjected to a subsequent distilling operation so that a cake, from foreign matter dissolved in this solvent, will form only in the second distilling vessel from which it can be discharged without interrupting the distilling process in the first distilling vessel.

llnited States Patent [191 Biesinger 1 1 Aug. 6, 1974 METHOD AND APPARATUS FOR 956,508 5/1910 Baker 159/43 x DISTILLING O SOLVENTS IN WHICH 2,732,009 [/1956 Thurlings 159/44 3,102,062 8/1963 Graham et 211.... 159/44 X FOREIGN MATTER IS DISSOLVED 3,563,861 2/1971 Fletcher 203/71 X Erwin Biesinger, Rottenburg, Germany Assignee: Seco Maschinenbau GmbH & Co.

KG, Rottenburg/Neckar, Germany Filed: Dec. 21, 1972 Appl. No.: 317,358

Inventor:

Foreign Application Priority Data Dec. 23, 1971 Germany 2164373 US. Cl 159/44, 159/23, 159/18 Int. Cl 801d 1/26, BOld 1/00 Field of Search 159/17, 17 P, 18, 28 C, 159/22, 23, 44, 34; 203/1, 4, 71 D, 11 D, 18; 134/12, l3, 10; 202/160; 196/132 References Cited UNITED STATES PATENTS 12/1905 Shaw 159/28 C X Primary Examiner-Jack Sofer v Attorney, Agent, or FirmMichael S. Striker 1 5 7 1 ABSTRACT A method and apparatus for distilling solvents in which foreign matter is dissolved, resulting for instance from treating of textile material. The solvent is fed in a first distilling vessel in which it is evaporated until the liquid solvents therein reaches a predetermined level, whereafter the remaining liquid solvent is discharged from the first into a second distilling vessel wherein the solvent is subjected to a subsequent distilling operation so that a cake, from foreign matter dissolved in this solvent, will form only in the second distilling vessel from which it can be discharged without interrupting the distilling process in the first distilling vessel.

4 Claims, 1 Drawing Figure PATENTEuwc 81974 q R 0 s N E D W C GM 7 mm" m m W UL 5 v W WV" E A m V V T N E w 0 S SOLVENT WITH FOREIGN MATTER DISSOLVED THEREIN HEATING FLUID HEATING FLUID METHOD AND APPARATUS FOR DISTILLING OF SOLVENTS IN WHICH FOREIGN MATTER IS DISSOLVED BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for evaporating solvents, especially of solvents which are used for treating of textile material and which after acting on the textile material are evaporated in a distilling apparatus.

In apparatus for treating textiles, for instance webs of woven or knitted textiles for subsequent surface treating of the textiles, dirt, fat, oil or similar foreign matter is removed by solvents from the textile material in greater amounts as are, for instance, removed from garments during chemical cleaning thereof. The solvents used for such treating of textile material thus contain large amounts of foreign matter dissolved therein and are transferred from the apparatus for treating the textile into an apparatus in which, by evaporating of the solvent, a separation of the foreign matter dissolved therein from the solvent is carried out. The thus resulting large amounts of dirt form in short time on the bottom of the distilling vessel a large viscous cake, or bake in a heavy layer onto the inner surface of the distilling vessel. Such heavy layers forming on the inner surface of the distilling vessel will detrimentally affect heat transfer from the heated wall of the vessel to the liquid solvent therein which has to be distilled, and, in addition, such layers forming on the inner surface of the distilling vessel will require that the latter be cleaned at relatively short time intervals, which necessarily will lead to an interruption of the treatment of the textiles. If the foreign matter in the solvent includes silicon, than the danger exists also that foam is formed in the distilling vessel.

} SUMMARY OF THE INVENTION It is an object of the present invention to avoid the above-mentioned disadvantages and to provide for a method and apparatus for distilling of solvents, especially for solvents resulting from the treatment of textile materials, in which an interruption of the treatment of the textile material may be avoided.

With these and other objects in view, which will become apparent as the description proceeds, the method according to the present invention of distilling of solvents in which foreign matter is dissolved mainly comprises the steps of evaporating the solvent in a first distilling vessel, interrupting the evaporation process in this first distilling vessel when the liquid solvent therein drops to a predetermined level, discharging the remaining liquid solvent from the first into a second distilling vessel and subjecting the remaining solvent in the second distilling vessel to subsequent evaporation process. This subsequent evaporation process may be carried out in a cycle which is completely independent from the cycle in which the solvent is fed into the first distilling vessel, that is therefore also independent from the cycle at which the treatment of the textile material is carried out. The method to the present invention will assure that the foreign matter dissolved in the solvent will be discharged from the first distilling vessel before it can form a viscous cake therein or bake onto the inner surface of the first distilling vessel. The interior of the first distilling vessel will therefore remain substantially clean and a cleaning thereof will be required only at very great time intervals. The remaining solvent with the foreign matter dissolved therein is then completely evaporated in the second distilling vessel which can be completely separated from the first distilling vessel so that the second distilling vessel can be cleaned without interrupting operation of the first distilling vessel.

The apparatus for carrying out the above-described method may comprise a first distilling vessel having an inlet opening for feeding liquid solvent in which foreign matter is dissolved thereinto and a solvent vapor outlet opening, a second-distilling vessel arranged below the first distilling vessel, conduit means providing communication between the lower portion of the first distilling vessel and the second distilling vessel, normally closed valve means in the conduit means, and control means for automatically opening the valve means in dependence of the level of liquid solvent in the first distilling vessel, and heating means for heating the first and the second distilling vessel. The heating means for the first distilling vessel may comprise indirect heating means for heating the first distilling vessel from the outside and additional heating means in the interior of the first distilling vessel, and at least the additional heating means may be controlled by the aforementioned control means to stop any heating action of the additional heating means upon opening the valve means. This will assure that when the remaining solvent is discharged from the first distilling vessel the heating of the latter may be completely interrupted or at least considerably reduced so as to avoid baking of any remaining thin film of solvent containing foreign matter onto the inner surface of the first distilling vessel.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single drawing schematically illustrates the distilling apparatus according of the present invention in a vertical cross section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawing, the distilling apparatus according to the present invention mainly comprises a main or first distilling vessel 10 provided with an inlet opening 11 through which solvent containing a relatively large amount of foreign matter dissolved therein, resulting for instance from a textile treating apparatus, not shown in the drawing, may be fed in a predetermined cycle, corresponding to the operation of the aforementioned textile treating apparatus, into the interior of the distilling vessel 10. The vessel 10 is further provided in its upper portion with a solvent vapor discharge outlet 12 through which the solvent vapors are transferred into a condenser, shown in the drawing. The distilling vessel 10 is provided, in known manner, at its lower portion thereof with a double wall forming a heating chamber 13 through which water vapor or an other heating medium is circulated, by means of the conduits l4 and 15, for indirectly heating the solvent fed into the vessel 10. Additional heating means in form of a tubular heating coil 16 are preferably arranged in the interior of the vessel through which a heating medium, for instance water vapor, is likewise circulated by the conduits l7 and 18 connected to the coil 16.

A second distilling vessel 20 is arranged below the first or main distilling vessel 10 and a conduit 21 provides communication between the interior of the first distilling vessel 10 in the region of the bottom portion of the latter and the interior of the second distilling vessel. The second distilling vessel may have substantially the same construction as the construction of the distilling vessel 10, and in the illustrated embodiment the second distilling vessel 20 is likewise indirectly heated by a heating chamber provided at the bottom portion thereof through which water vapor or another heating medium is circulated. While the second distilling vessel is shown in the drawing as being of the same size as the first heating vessel 10, the size of the second distilling vessel can actually be chosen to be different from that of the first distilling vessel. The necessary solvent vapor outlet for the second distilling vessel is shown in the drawing and this outlet is likewise connected to the above-mentioned condenser.

Normally closed valve means 22 are arranged in the conduit 21, and this valve means 22 may be opened in a known manner by electromagnetic means 23 connected thereto when the electromagnetic means are energized. Level sensing means 26 are arranged in the interior of the first distilling vessel 10 for imparting a signal to control means connected thereto when the level of the liquid solvent in the main distilling vessel 10 drops, after evaporation, a predetermined level indicated by the dash-dot line 27. The control means 25 are constructed, in a known manner not forming part of the present invention, to energize the electromagnetic means 23 to open the valve means 22 when the liquid solvent in the vessel 10 drops to the level indicated by the dash-dot line 27 so that the remaining liquid solvent is discharged from the first distilling vessel 10 into the second distilling vessel 20.

When after evaporation of the solvent in the first distilling vessel the level of liquid solvent drops to the level as indicated by the dash-dot line 27, heating of the distilling vessel 10 is interrupted so that further evaporation of liquid solvent in the first distilling vessel 10 will substantially cease. This interruption of further heating of the first distilling vessel 10 is preferably automatically performed, and the control means 25 may also be connected for this purpose to the valve 19 in the vapor inlet conduit 17 of the heating coil 16 and to a similar valve 30, connected to the vapor inlet conduit 14 of the heating chamber 13 so that further heating of the vessel 10 will be interrupted when the liquid solvent therein reaches the level indicated by the dash-dot line 27. Feeding of the heating medium to the coil 16, which mainly serves to quickly heat up the solvent discharged in cold condition into the heating vessel 10, may also be stopped before the liquid solvent in the vessel 10 reaches the predetermined level 27 by controlling sliut off of the valve 19 in a known manner in dependence on the temperature reached by the solvent in the distilling vessel 10. For this purpose temperature sensing means 28, may be provided in the interior of the vessel 10 and operatively connected to the valve 19. After stopping of the further evaporation process in the distilling vessel 10, the valve means 22 are opened by energizing the electromagnetic means 23 through the control means 25 so that the remaining liquid solvent containing a large amount of foreign matter dissolved therein is discharged through the conduit 21 into the second distilling chamber 20. The thus discharged amount of solvent alone or together with solvent remainders from previous charges are evaporated in the second distilling vessel in a cycle which is completely independent from the cycle at which the first distilling vessel It) is operated, that is also completely independent from the cycle at which the textile treating apparatus is operated from which the solvent containing the foreign matter results, which is fed into the first distilling vessel 10.

The valve means 22 are closed again as soon as the remaining solvent is discharged from the distilling vessel into distilling vessel 20 and the distilling vessel 10 may be supplied immediately subsequent thereto with new solvent containing foreign matter dissolved therein.

The second distilling vessel 20 is constructed, in a known manner at a door 31 which can be easily opened so that a cake forming therein from the foreign matter in the solvent, after complete evaporation of the latter, may be easily discharged at selected time intervals therefrom during such time when the valve means 22 are closed, while the first distilling vessel 10 is in operation. Since no cake will form in the distilling vessel 10, a cleaning of the latter will be necessary only at very great time intervals.

it will be understood that each of the elements described above or two or more together, may also find a useful application in other types of method and apparatus for distilling solvents in which foreign matter is dissolved differing from the types described above.

While the invention has been illustrated and described as embodied in a method and apparatus for distilling solvents in which foreign matter is dissolved, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. Apparatus for evaporating a solvent in which foreign matter is dissolved comprising, in combination, a first, vented evaporating vessel having an inlet opening for feeding liquid solvent in which foreign matter is dissolved and a solvent vapor outlet; a second substantially closed evaporating vessel arranged below said first vessel; conduit means providing communication between a lower portion of said first vessel with said second vessel; normally closed valve means in said conduit means; control means for automatically opening said valve means in dependence on the level of liquid in said first vessel, said control means comprising liquid v level sensing means in said first vessel, electromagnet means connected to said valve means for opening the latter when energized, and a control device in circuit with said liquid level sensing means and said electromagnet means for energizing the latter when the liquid solvent in said first vessel drops to a predetermined level; and heating means for indirectly heating said first and second vessels.

2. Apparatus for evaporating of solvent in which foreign matter is dissolved comprising, in combination, a first, vented evaporating vessel having an inlet opening for feeding liquid solvent in which foreign matter is dissolved and a solvent vapor outlet opening; a second substantially closed, vented evaporating vessel arranged below said first vessel; conduit means providing communication between a lower portion of said first vessel and said second vessel; normally closed valve means in said conduit means; heating means for said first vessel comprising indirect heating means for heating said first vessel from the outside and additional indirect heating means in the interior of said first vessel; and control means for automatically opening said valve means in dependence of the level of liquid in said first vessel and for stopping any heating action of said additional heating means when the liquid in said first vessel drops to a predetermined level.

3. A method of evaporating solvents in which foreign matter is dissolved comprising the steps of feeding a given quantity of such solvents with foreign matter dissolved therein into a first vented evaporating vessel; indirectly heating the liquid solvent in said first vessel by heating the outer surface thereof and additionally by indirectly heating the liquid from within the first vessel; stopping at least said indirect heating of the liquid from within said first vessel when the liquid in said first vessel drops to a predetermined level; discharging the remaining liquid solvent and contained foreign matter from said first into a second indirectly heated, vented evaporating; closed vessel; and subjecting the remaining liquid in said second vessel to a subsequent evaporating process.

4. A method as defined in claim 3, and including the step of sensing when the liquid in said first vessel drops to said predetermined level and automatically stopping at least said indirect heating of said liquid within said first vessel when said predetermined level is reached. 

1. Apparatus for evaporating a solvent in which foreign matter is dissolved comprising, in combination, a first, vented evaporating vessel having an inlet opening for feeding liquid solvent in which foreign matter is dissolved and a solvent vapor outlet; a second substantially closed evaporating vessel arranged below said first vessel; conduit means providing communication between a lower portion of said first vessel with said second vessel; normally closed valve means in said conduit means; control means for automatically opening said valve means in dependence on the level of liquid in said first vessel, said control means comprising liquid level sensing means in said first vessel, electromagnet means connected to said valve means for opening the latter when energized, and a control device in circuit with said liquid level sensing means and said electromagnet means for energizing the latter when the liquid solvent in said first vessel drops to a predetermined level; and heating means for indirectly heating said first and second vessels.
 2. Apparatus for evaporating of solvent in which foreign matter is dissolved comprising, in combination, a first, vented evaporating vessel having an inlet opening for feeding liquid solvent in which foreign matter is dissolved and a solvent vapor outlet opening; a second substantially closed, vented evaporating vessel arranged below said first vessel; conduit means providing communication between a lower portion of said first vessel and said second vessel; normally closed valve means in said conduit means; heating means for said first vesseL comprising indirect heating means for heating said first vessel from the outside and additional indirect heating means in the interior of said first vessel; and control means for automatically opening said valve means in dependence of the level of liquid in said first vessel and for stopping any heating action of said additional heating means when the liquid in said first vessel drops to a predetermined level.
 3. A method of evaporating solvents in which foreign matter is dissolved comprising the steps of feeding a given quantity of such solvents with foreign matter dissolved therein into a first vented evaporating vessel; indirectly heating the liquid solvent in said first vessel by heating the outer surface thereof and additionally by indirectly heating the liquid from within the first vessel; stopping at least said indirect heating of the liquid from within said first vessel when the liquid in said first vessel drops to a predetermined level; discharging the remaining liquid solvent and contained foreign matter from said first into a second indirectly heated, vented evaporating; closed vessel; and subjecting the remaining liquid in said second vessel to a subsequent evaporating process.
 4. A method as defined in claim 3, and including the step of sensing when the liquid in said first vessel drops to said predetermined level and automatically stopping at least said indirect heating of said liquid within said first vessel when said predetermined level is reached. 